Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 336 insertions, 0 deletions

diff --git a/trace/control.c b/trace/control.c
new file mode 100644
index 000000000..d5b68e846
--- /dev/null
+++ b/trace/control.c
@@ -0,0 +1,336 @@
+/*
+ * Interface for configuring and controlling the state of tracing events.
+ *
+ * Copyright (C) 2011-2016 Lluís Vilanova <vilanova@ac.upc.edu>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "trace/control.h"
+#include "qemu/help_option.h"
+#include "qemu/option.h"
+#ifdef CONFIG_TRACE_SIMPLE
+#include "trace/simple.h"
+#endif
+#ifdef CONFIG_TRACE_FTRACE
+#include "trace/ftrace.h"
+#endif
+#ifdef CONFIG_TRACE_LOG
+#include "qemu/log.h"
+#endif
+#ifdef CONFIG_TRACE_SYSLOG
+#include <syslog.h>
+#endif
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "qemu/config-file.h"
+#include "monitor/monitor.h"
+#include "trace/trace-root.h"
+
+int trace_events_enabled_count;
+
+typedef struct TraceEventGroup {
+    TraceEvent **events;
+} TraceEventGroup;
+
+static TraceEventGroup *event_groups;
+static size_t nevent_groups;
+static uint32_t next_id;
+static uint32_t next_vcpu_id;
+static bool init_trace_on_startup;
+static char *trace_opts_file;
+
+QemuOptsList qemu_trace_opts = {
+    .name = "trace",
+    .implied_opt_name = "enable",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
+    .desc = {
+        {
+            .name = "enable",
+            .type = QEMU_OPT_STRING,
+        },
+        {
+            .name = "events",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "file",
+            .type = QEMU_OPT_STRING,
+        },
+        { /* end of list */ }
+    },
+};
+
+
+void trace_event_register_group(TraceEvent **events)
+{
+    size_t i;
+    for (i = 0; events[i] != NULL; i++) {
+        events[i]->id = next_id++;
+        if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) {
+            continue;
+        }
+
+        if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) {
+            events[i]->vcpu_id = next_vcpu_id++;
+        } else {
+            warn_report("too many vcpu trace events; dropping '%s'",
+                        events[i]->name);
+        }
+    }
+    event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
+    event_groups[nevent_groups].events = events;
+    nevent_groups++;
+
+#ifdef CONFIG_TRACE_SIMPLE
+    st_init_group(nevent_groups - 1);
+#endif
+}
+
+
+TraceEvent *trace_event_name(const char *name)
+{
+    assert(name != NULL);
+
+    TraceEventIter iter;
+    TraceEvent *ev;
+    trace_event_iter_init_all(&iter);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
+        if (strcmp(trace_event_get_name(ev), name) == 0) {
+            return ev;
+        }
+    }
+    return NULL;
+}
+
+void trace_event_iter_init_all(TraceEventIter *iter)
+{
+    iter->event = 0;
+    iter->group = 0;
+    iter->group_id = -1;
+    iter->pattern = NULL;
+}
+
+void trace_event_iter_init_pattern(TraceEventIter *iter, const char *pattern)
+{
+    trace_event_iter_init_all(iter);
+    iter->pattern = pattern;
+}
+
+void trace_event_iter_init_group(TraceEventIter *iter, size_t group_id)
+{
+    trace_event_iter_init_all(iter);
+    iter->group_id = group_id;
+}
+
+TraceEvent *trace_event_iter_next(TraceEventIter *iter)
+{
+    while (iter->group < nevent_groups &&
+           event_groups[iter->group].events[iter->event] != NULL) {
+        TraceEvent *ev = event_groups[iter->group].events[iter->event];
+        size_t group = iter->group;
+        iter->event++;
+        if (event_groups[iter->group].events[iter->event] == NULL) {
+            iter->event = 0;
+            iter->group++;
+        }
+        if (iter->pattern &&
+            !g_pattern_match_simple(iter->pattern, trace_event_get_name(ev))) {
+            continue;
+        }
+        if (iter->group_id != -1 &&
+            iter->group_id != group) {
+            continue;
+        }
+        return ev;
+    }
+
+    return NULL;
+}
+
+void trace_list_events(FILE *f)
+{
+    TraceEventIter iter;
+    TraceEvent *ev;
+    trace_event_iter_init_all(&iter);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
+        fprintf(f, "%s\n", trace_event_get_name(ev));
+    }
+#ifdef CONFIG_TRACE_DTRACE
+    fprintf(f, "This list of names of trace points may be incomplete "
+               "when using the DTrace/SystemTap backends.\n"
+               "Run 'qemu-trace-stap list %s' to print the full list.\n",
+            error_get_progname());
+#endif
+}
+
+static void do_trace_enable_events(const char *line_buf)
+{
+    const bool enable = ('-' != line_buf[0]);
+    const char *line_ptr = enable ? line_buf : line_buf + 1;
+    TraceEventIter iter;
+    TraceEvent *ev;
+    bool is_pattern = trace_event_is_pattern(line_ptr);
+
+    trace_event_iter_init_pattern(&iter, line_ptr);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
+        if (!trace_event_get_state_static(ev)) {
+            if (!is_pattern) {
+                warn_report("trace event '%s' is not traceable",
+                            line_ptr);
+                return;
+            }
+            continue;
+        }
+
+        /* start tracing */
+        trace_event_set_state_dynamic(ev, enable);
+        if (!is_pattern) {
+            return;
+        }
+    }
+
+    if (!is_pattern) {
+        warn_report("trace event '%s' does not exist",
+                    line_ptr);
+    }
+}
+
+void trace_enable_events(const char *line_buf)
+{
+    if (is_help_option(line_buf)) {
+        trace_list_events(stdout);
+        if (monitor_cur() == NULL) {
+            exit(0);
+        }
+    } else {
+        do_trace_enable_events(line_buf);
+    }
+}
+
+static void trace_init_events(const char *fname)
+{
+    Location loc;
+    FILE *fp;
+    char line_buf[1024];
+    size_t line_idx = 0;
+
+    if (fname == NULL) {
+        return;
+    }
+
+    loc_push_none(&loc);
+    loc_set_file(fname, 0);
+    fp = fopen(fname, "r");
+    if (!fp) {
+        error_report("%s", strerror(errno));
+        exit(1);
+    }
+    while (fgets(line_buf, sizeof(line_buf), fp)) {
+        loc_set_file(fname, ++line_idx);
+        size_t len = strlen(line_buf);
+        if (len > 1) {              /* skip empty lines */
+            line_buf[len - 1] = '\0';
+            if ('#' == line_buf[0]) { /* skip commented lines */
+                continue;
+            }
+            trace_enable_events(line_buf);
+        }
+    }
+    if (fclose(fp) != 0) {
+        loc_set_file(fname, 0);
+        error_report("%s", strerror(errno));
+        exit(1);
+    }
+    loc_pop(&loc);
+}
+
+void trace_init_file(void)
+{
+#ifdef CONFIG_TRACE_SIMPLE
+    st_set_trace_file(trace_opts_file);
+    if (init_trace_on_startup) {
+        st_set_trace_file_enabled(true);
+    }
+#elif defined CONFIG_TRACE_LOG
+    /*
+     * If both the simple and the log backends are enabled, "--trace file"
+     * only applies to the simple backend; use "-D" for the log
+     * backend. However we should only override -D if we actually have
+     * something to override it with.
+     */
+    if (trace_opts_file) {
+        qemu_set_log_filename(trace_opts_file, &error_fatal);
+    }
+#else
+    if (trace_opts_file) {
+        fprintf(stderr, "error: --trace file=...: "
+                "option not supported by the selected tracing backends\n");
+        exit(1);
+    }
+#endif
+}
+
+void trace_fini_vcpu(CPUState *vcpu)
+{
+    TraceEventIter iter;
+    TraceEvent *ev;
+
+    trace_guest_cpu_exit(vcpu);
+
+    trace_event_iter_init_all(&iter);
+    while ((ev = trace_event_iter_next(&iter)) != NULL) {
+        if (trace_event_is_vcpu(ev) &&
+            trace_event_get_state_static(ev) &&
+            trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
+            /* must disable to affect the global counter */
+            trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
+        }
+    }
+}
+
+bool trace_init_backends(void)
+{
+#ifdef CONFIG_TRACE_SIMPLE
+    if (!st_init()) {
+        fprintf(stderr, "failed to initialize simple tracing backend.\n");
+        return false;
+    }
+#endif
+
+#ifdef CONFIG_TRACE_FTRACE
+    if (!ftrace_init()) {
+        fprintf(stderr, "failed to initialize ftrace backend.\n");
+        return false;
+    }
+#endif
+
+#ifdef CONFIG_TRACE_SYSLOG
+    openlog(NULL, LOG_PID, LOG_DAEMON);
+#endif
+
+    return true;
+}
+
+void trace_opt_parse(const char *optarg)
+{
+    QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
+                                             optarg, true);
+    if (!opts) {
+        exit(1);
+    }
+    if (qemu_opt_get(opts, "enable")) {
+        trace_enable_events(qemu_opt_get(opts, "enable"));
+    }
+    trace_init_events(qemu_opt_get(opts, "events"));
+    init_trace_on_startup = true;
+    g_free(trace_opts_file);
+    trace_opts_file = g_strdup(qemu_opt_get(opts, "file"));
+    qemu_opts_del(opts);
+}
+
+uint32_t trace_get_vcpu_event_count(void)
+{
+    return next_vcpu_id;
+}